-7CASTLE.
The CASTLE Rad. Safe. surveys were generally made
between0000 and 1100 local time except on shot days, when they
were generally made between 1200 and 1400. For the helicopter
measurements the dats were converted to ground readings by use of
the correlation curve for air to ground readings from the report
on Radiological Safety Operations for the Upshot-Knothole series.
Accor
to the Project 2.5a Final Report, fallout after
Shot 1 (BRAVO) began on the southern and eastern islands of the
atoll and at the lagoon stations approximately 1/2 to 1-1/2 hours
after the detonation. The mean diameter of the particles observed
for several of these stations was about 90 microns. These times
of arrival and this particle size are inconsistent with the normal
fallout process, and some mechanism other than transport by the
wind of individual falling particles is sugrested. A possible
mechanism may be descent in rain drops from the column of water
which constituted the bulk of the visible nuclear clow. It is
believed that part of the colum drifted to ths south snd east.
Also, in WI-917 the character of some of tha lagoon samples in
question was described as a slurry defined in oné section of ths
report as "the appearance of sea water plus slaked lime suspension"
and in another described merely as being wet. The chemical anslysis
of some of the pertinent semples reported as wet when collected
showed no evidence of sea water, so that whatever moisture was
present probably came fran rain water.
ad
For Shot 6 (NECTAR) the Red. Safe. readings ware made approxi-
ie
mately one day after the detonation, but to avoid further clutter-
ing the D + 1 has been omitted from Figure 1.
?
WIND DATA
For seach of the bursts considered in this repart an attempt
was made to estimate the mean winds at shot time through various
layers in the atmosphere to the 5,000 foot level nearest to the
top of the cloud. These were generally obtained by plotting the
balloon position as a function of height, based on the original
readings of azimuth and elevation angles, ami the ship's course and
speed in the case of shipboard soundings, Then the selected alti- |
tudes between which mean winds were desired were interpolated on the
curve and the vector displecements between successive heights were
measured end the mean speeds and directions obtained. In a few
cases where the ariginsl data were unavailable, the published
coded wind massages were used to estimte the man winds. Usually,
the mean winds were obtained for a sounding before ahd a sounding
,
‘
4
4
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